Presently available waveguide hybrids are comprised of adjacent waveguides which share a common narrow wall, with the common wall having a central opening formed therein to provide a coupling window. One of the waveguides serves as the primary waveguide and the other serves as the secondary or auxiliary waveguide. An excitation signal, generally a microwave signal, is impressed upon the input port of the primary waveguide and thence propagates in a TE.sub.10 mode through the primary waveguide towards the output port thereof. A portion of the wave energy is radiated into the auxiliary waveguide through the coupling window. A series of capacitive blocks, oftentimes referred to as side blocks, are provided along the floor of each of the waveguides adjacent to the outside narrow walls thereof, in proximity to the coupling window, to thereby provide what is commonly referred to as a squeezed waveguide seciton, in order to facilitate optimum coupling efficiency.
Although these currently available waveguide hybrids perform in a satisfactory manner, they are unnecessarily large and difficult to fabricate. In certain applications, such as spaceborne satellite applications, where space is at a premium, and large numbers of hybrids are employed in the antenna feed network, the size and weight of the hybrids becomes a major consideration and design constraint. Although many efforts have been made in the past to reduce the size of waveguide hybrids, there still exists a need to further reduce their size, especially as the satellite antenna designs become increasingly complex and cumbersome. Further, because of the large numbers of hybrids employed in such designs, there also exists a need to simplify and render less expensive the manufacture of these waveguide hybrids.
The present invention addresses and satisfies these needs, thereby overcoming the shortcomings and limitations of the currently available waveguide hybrids.